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arXiv · 1901.08388

Ultrafast transient increase of oxygen octahedral rotations in a perovskite

M. Porer·M. Fechner·M. Kubli·M. J. Neugebauer·S. Parchenko·V. Esposito·A. Narayan·N. A. Spaldin·R. Huber·M. Radovic·E. M. Bothschafter·J. M. Glownia·T. Sato·S. Song·S. L. Johnson·U. Staub
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Abstract

The ability to control the structure of a crystalline solid on ultrafast timescales bears enormous potential for information storage and manipulation or generating new functional states of matter [1]. In many materials where the ultrafast control of crystalline structures has been explored, optical excitation pushes materials towards their less ordered high temperature phase [2{9] as electronically driven ordered phases melt and possible concomitant structural modifications relax. Nonetheless, for a few select materials it has been shown that photoexcitation can slightly enhance the amplitude of an electronic ordering phenomenon (i.e. its electronic order parameter) [9{13]. Here we show via femtosecond hard X-ray diffraction that photodoping of the perovskite EuTiO3 transiently increases the order parameter associated with a purely structural [14] phase transition represented by the antiferrodistortive rotation of the oxygen octahedra. This can be understood from an ultrafast charge-transfer induced reduction of the Goldschmidt tolerance factor [15], which is a fundamental control parameter for the properties of perovskites

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M. Porer, M. Fechner, M. Kubli, M. J. Neugebauer, S. Parchenko, V. Esposito, A. Narayan, N. A. Spaldin, R. Huber, M. Radovic, E. M. Bothschafter, J. M. Glownia, T. Sato, S. Song, S. L. Johnson, U. Staub. 2019-01-24. Ultrafast transient increase of oxygen octahedral rotations in a perovskite. https://doi.org/10.1103/physrevresearch.1.012005

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